General above-stump volume and biomass functions for Pinus radiata, Eucalyptus globulus and Eucalyptus nitens

Abstract

Accurate estimations of stem volume and tree component biomass are of paramount importance for the study and management of forests. In Chile, the most important commercial tree species are Pinus radiata, Eucalyptus globulus and Eucalyptus nitens, which are successfully planted in other parts of the world. Available individual-tree allometric models are typically local models which do not include age or stand scale covariates and rely solely on stem diameter outside bark at breast height (DBH) and, in some cases, total tree height (H). We used data from 1571 trees across the distribution of the three species in Chile to develop general individual-tree equations for stem volume inside and outside bark, and biomass components (dead branch, live branch, foliage, bark and stem wood inside and outside bark). Our models include DBH or DBH and H as predicting variables, as well as stand-level variables like age, basal area and stand density. General allometric models that include stand-level variables have not been previously reported for P. radiata, E. globulus and E. nitens. Given the broad area of inference in our data, the models are applicable over a large geographical area and a variety of stand ages and characteristics and can be used to support management decisions or integrated in stand-level productivity models to enhance the accuracy and precision of model outputs. The collective effort behind this study is a remarkable example of cooperation across researchers and practitioners in order to address complex questions in a transdisciplinary world.